THE DYNAMICS OF DIFFERENT DEVELOPMENTAL STAGES IN NATURAL ORIENTAL BEECH ( Fagus orientalis LIPSKY) STANDS IN NORTHERN IRAN

Present study was carried out in natural oriental beech stands created by regeneration and without human technical interference, located in one district, compartment 128 (the reserve compartment or untouched)of management plan in Shamoushak of Gorgan in northern Iran, on 2013. After the primary forest tour, 5-hectare sample plots were selected and each were divided into 1-hectare plots (100×100 m) and also, two transects each with a size of 10×100m (1000 m^2) were selected and to assess the regeneration, 9 micro sample plots each with a size of 3×3 (9 m^2) were considered inside the transects. A %100 inventory (full callipering) was done on all of the stand’s parameters including diameter at breast height (dbh), snags, height of the trees, natural regeneration, quality of tree trunks and canopy condition. Then, considering the developmental stages and phases defined in reserve forests and adapting these theories with current condition of the studied stand, the results showed that, abundance of the trees in the initial stage has been decreased compared to optimal and decay stages. The highest volume has been in optimal stage and the lowest has been in decay stage. The highest volume of dead and fallen trees has been in decay stage and with opening of the canopy cover in this stage, regeneration is increased. In terms of heights of the trees, in optimal stage, the stand is of single-story type with low height differences and quality of the tree trunks has been increased in this stage. Number increase in the first diameter class in the initial stage implies regeneration of revitalization. Through thinning operations in optimal stage, we can obtain creation of mixed stands with rich and stable structures).